If you do the work suggested in https://www.jetbrains.com/help/pycharm/type-hinting-in-pycha... which references https://www.python.org/dev/peps/pep-0484/ and https://www.python.org/dev/peps/pep-0526/ then it can do a pretty good (though not perfect) job. That said...getting it there can take quite a bit of work, particularly w.r.t. third-party libraries.